Test transparent huge pages on Linux (#278)

* Adding ability to use THP on Linux

* Use the actual page size4 used for mmap also in munmap

* Add -thp to llama-bench

---------

Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>
This commit is contained in:
Kawrakow
2025-03-23 07:24:43 +01:00
committed by GitHub
parent 37c48feb3e
commit 79a105d8ab
5 changed files with 99 additions and 13 deletions

View File

@@ -1827,6 +1827,7 @@ using llama_files = std::vector<std::unique_ptr<llama_file>>;
struct llama_mmap {
void * addr;
size_t size;
size_t mapped_page_size = 0;
llama_mmap(const llama_mmap &) = delete;
@@ -1836,7 +1837,7 @@ struct llama_mmap {
// list of mapped fragments (first_offset, last_offset)
std::vector<std::pair<size_t, size_t>> mapped_fragments;
llama_mmap(struct llama_file * file, size_t prefetch = (size_t) -1 /* -1 = max value */, bool numa = false) {
llama_mmap(struct llama_file * file, size_t prefetch = (size_t) -1 /* -1 = max value */, bool numa = false, [[maybe_unused]] bool use_thp = false) {
size = file->size;
int fd = fileno(file->fp);
int flags = MAP_SHARED;
@@ -1849,6 +1850,29 @@ struct llama_mmap {
strerror(errno));
}
if (prefetch) { flags |= MAP_POPULATE; }
if (use_thp) {
size_t huge = get_default_huge_page_size();
auto size = huge*((file->size + huge - 1)/huge);
addr = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
if (addr != MAP_FAILED) {
printf("%s: using THP with page size %zu MiB ", __func__, huge/(1024*1024));
fflush(stdout);
size_t tot = 0;
while (tot < file->size) {
auto n_read = pread(fd, static_cast<char*>(addr) + tot, file->size - tot, tot);
if (n_read < 0) throw std::runtime_error(format("Reading into mapped huge pages failed at %zu (%s)", tot, strerror(errno)));
printf("."); fflush(stdout);
tot += n_read;
}
printf(" done\n");
mapped_fragments.emplace_back(0, file->size);
mapped_page_size = huge;
return;
}
else {
fprintf(stderr, "%s: mmap with huge page size %zu MiB failed (%s)\n", __func__, huge/(1024*1024), strerror(errno));
}
}
#endif
addr = mmap(NULL, file->size, PROT_READ, flags, fd, 0);
if (addr == MAP_FAILED) { // NOLINT
@@ -1893,7 +1917,7 @@ struct llama_mmap {
void unmap_fragment(size_t first, size_t last) {
// note: this function must not be called multiple times with overlapping ranges
// otherwise, there is a risk of invalidating addresses that have been repurposed for other mappings
int page_size = sysconf(_SC_PAGESIZE);
int page_size = mapped_page_size > 0 ? mapped_page_size : sysconf(_SC_PAGESIZE);
align_range(&first, &last, page_size);
size_t len = last - first;
@@ -1935,6 +1959,28 @@ struct llama_mmap {
mapped_fragments = std::move(new_mapped_fragments);
}
#ifdef __linux__
static int get_default_huge_page_size() {
int pg_size = 2048;
std::ifstream in("/proc/meminfo");
if (in) {
std::string line;
while (true) {
std::getline(in, line);
if (in.fail()) break;
if (auto pos = line.find("Hugepagesize:"); pos != std::string::npos) {
std::istringstream str(line.data() + pos + 13);
int aux;
str >> aux;
if (!str.fail()) pg_size = aux;
break;
}
}
}
return pg_size * 1024;
}
#endif
~llama_mmap() {
for (const auto & frag : mapped_fragments) {
if (munmap((char *) addr + frag.first, frag.second - frag.first)) {
@@ -1945,7 +1991,7 @@ struct llama_mmap {
#elif defined(_WIN32)
static constexpr bool SUPPORTED = true;
llama_mmap(struct llama_file * file, size_t prefetch = (size_t) -1, bool numa = false) {
llama_mmap(struct llama_file * file, size_t prefetch = (size_t) -1, bool numa = false, [[maybe_unused]] bool use_thp = false) {
GGML_UNUSED(numa);
size = file->size;
@@ -2007,10 +2053,11 @@ struct llama_mmap {
#else
static constexpr bool SUPPORTED = false;
llama_mmap(struct llama_file * file, size_t prefetch = -1, bool numa = false) {
llama_mmap(struct llama_file * file, size_t prefetch = -1, bool numa = false, bool use_thp = false) {
GGML_UNUSED(file);
GGML_UNUSED(prefetch);
GGML_UNUSED(numa);
GGML_UNUSED(use_thp);
throw std::runtime_error("mmap not supported");
}
@@ -3842,6 +3889,7 @@ struct llama_model_loader {
bool use_mmap = false;
bool check_tensors;
bool repack_tensors = false;
bool use_thp = false;
llama_files files;
llama_ftype ftype;
@@ -3876,7 +3924,7 @@ struct llama_model_loader {
std::string arch_name;
LLM_KV llm_kv = LLM_KV(LLM_ARCH_UNKNOWN);
llama_model_loader(const std::string & fname, bool use_mmap, bool check_tensors, bool repack_tensors,
llama_model_loader(const std::string & fname, bool use_mmap, bool check_tensors, bool repack_tensors, bool use_thp,
const llama_model_kv_override * param_overrides_p,
const llama_model_tensor_buft_override * param_tensor_buft_overrides_p) {
int trace = 0;
@@ -4140,6 +4188,7 @@ struct llama_model_loader {
this->use_mmap = use_mmap;
this->check_tensors = check_tensors;
this->repack_tensors = repack_tensors;
this->use_thp = use_thp;
}
~llama_model_loader() {
@@ -4453,12 +4502,12 @@ struct llama_model_loader {
}
}
void init_mappings(bool prefetch = true, llama_mlocks * mlock_mmaps = nullptr) {
void init_mappings(bool prefetch = true, llama_mlocks * mlock_mmaps = nullptr, bool use_thp = false) {
if (use_mmap) {
mappings.reserve(files.size());
mmaps_used.reserve(files.size());
for (const auto & file : files) {
std::unique_ptr<llama_mmap> mapping(new llama_mmap(file.get(), prefetch ? -1 : 0, ggml_is_numa()));
std::unique_ptr<llama_mmap> mapping(new llama_mmap(file.get(), prefetch ? -1 : 0, ggml_is_numa(), use_thp));
mmaps_used.emplace_back(mapping->size, 0);
if (mlock_mmaps) {
std::unique_ptr<llama_mlock> mlock_mmap(new llama_mlock());
@@ -8077,7 +8126,7 @@ static bool llm_load_tensors(
ml.done_getting_tensors();
ml.init_mappings(true, use_mlock ? &model.mlock_mmaps : nullptr);
ml.init_mappings(true, use_mlock ? &model.mlock_mmaps : nullptr, ml.use_thp);
model.mappings.reserve(ml.mappings.size());
// create the backend buffers
@@ -8410,7 +8459,7 @@ static bool llm_load_tensors(
static int llama_model_load(const std::string & fname, llama_model & model, llama_model_params & params) {
try {
llama_model_loader ml(fname, params.use_mmap, params.check_tensors,
params.repack_tensors, params.kv_overrides, params.tensor_buft_overrides);
params.repack_tensors, params.use_thp, params.kv_overrides, params.tensor_buft_overrides);
model.hparams.vocab_only = params.vocab_only;
@@ -17494,7 +17543,7 @@ static void llama_model_quantize_internal(const std::string & fname_inp, const s
auto v = (std::vector<llama_model_kv_override>*)params->kv_overrides;
kv_overrides = v->data();
}
llama_model_loader ml(fname_inp, use_mmap, /*check_tensors*/ true, /* repack_tensors */ false, kv_overrides, nullptr);
llama_model_loader ml(fname_inp, use_mmap, /*check_tensors*/ true, /* repack_tensors */ false, /* use_thp */ false, kv_overrides, nullptr);
ml.init_mappings(false); // no prefetching
llama_model model;
@@ -18318,6 +18367,7 @@ struct llama_model_params llama_model_default_params() {
/*.use_mlock =*/ false,
/*.check_tensors =*/ false,
/*.repack_tensors =*/ false,
/*.use_thp =*/ false,
};
#ifdef GGML_USE_METAL